Aspects of the disclosure relate to location-based services for mobile wireless devices. In particular, various aspects of the disclosure relate to Secure User Plan Location (SUPL) technology.
Location services for mobile wireless devices enable the current location and optionally speed and heading of a mobile wireless device to be obtained and provided to the wireless device (e.g., to an application running on the wireless device or to the user of the wireless device) or to some third party. Examples of a third party may include an emergency services provider (e.g., in the case of an emergency call from the wireless device) or some external provider of commercial services that depend on knowing the current or previous location of the wireless device. For wireless devices that may access different types of wireless communication networks, location services may be supported using a location server that can be accessed from and, in some cases, may be resident within the wireless network currently being accessed by the wireless terminal. The role of the location server may be (i) to assist the wireless terminal to make appropriate location related measurements (e.g., measurements of radio signals from base stations in the serving wireless network or measurements of various global navigation satellites) and, in some cases, (ii) to compute the location of the wireless terminal based on these measurements. The location server may also be used to relay a wireless device's location to entities authorized to receive the location and convey the wireless device's location to the wireless device in the event that the location server, rather than wireless device, had computed the location.
Current user plane location services, such as the Secure User Plane Location (SUPL) service defined by the Open Mobile Alliance (OMA), derive their security from mutual authentication between a target mobile device (e.g., a SUPL Enabled Terminal (SET)) and a location server (e.g., a SUPL Location Platform (SLP)) in which each party verifies the identity of the other party in a fully reliable manner.
A home location server (e.g., a Home SLP (H-SLP) in the case of SUPL) is a location server permanently affiliated with a number of target devices (e.g., based on service subscription). A home location server would sometimes belong to a home network operator of the target device, in the case of mobile wireless devices. A location server without a pre-provisioned permanent affiliation with a set of target devices may be referred to as a discovered location server.
In the case of SUPL, a discovered location server is referred to as a Discovered SLP (D-SLP). A discovered location server can be found by, or provided to, a target device based on its current location, currently used access network(s) and/or the current date and time and could belong to or be associated with, a non-home network operator or some other non-operator provider of location services. A Discovered SLP (D-SLP) is an SLP able to provide service to a SET in areas where the H-SLP is unable to provide service or unable to provide service at the requested quality of service (e.g., accuracy, time to fix).
In some instance (i.e., certain locations or environments), a H-SLP may not be able to adequately aid the SET in positioning (e.g., provide appropriate assistance data, perform positioning calculation, etc.). In these instances, a D-SLP may have a better ability than the H-SLP to aid the SET in positioning (e.g., provide appropriate assistance data, perform positioning calculation, etc.). In such instances a D-SLP may be used to provide unproved (e.g., localized) location service to a SET. A H-SLP may negotiate with a D-SLP to allow a SET to have access to the D-SLP. When a SET discovers a D-SLP, the SET may query its H-SLP for access rights to that D-SLP through an authorization process.
After D-SLP Authorization by an H-SLP, a SET may only be allowed to access the D-SLP while within the D-SLP service area. To this end, the SET needs to be able to determine whether it is inside or outside the D-SLP service area. This requires the SET to continuously monitor its position relative to the D-SLP service area by using high accuracy positioning methods. This continuous monitoring typically increases the power consumption of the SET and may more quickly drain the battery of the SET. Therefore, the continuous monitoring using precise positioning can reduce standby and usage time.